Maximum Occurrence (MaxOcc) refers to a method for making rigorous numerical assessments
about the maximum percent of time that a conformer of a flexible macromolecule can exist and
still be compatible with the experimental data. Maximum Occurrence of a conformer is defined
as the maximum weight that it can have in one ensemble that matches the average experimental data.
To evaluate the Maximum Occurrence, an ensemble is sought so that the conformation under investigation
is contained up to a certain value. At the Maximum Occurrence, no solution will be found fulfilling
both the requisites of containing the desired conformation and of being compatible with the experimental
data. Such process is exemplified in figure: the four boxes represent 4 different ensembles, containing
the desired conformation (represented as a red star) at different weight (represented by the dimension of
the red star): the fourth one is no more compatible with the experimental data.